Data communication networks are commonly used to transport data between end users. In many cases, virtual connections are established between particular end users to facilitate the transport of data. In some instances, these connections are switched virtual connections, or switched virtual circuits, whereas in other cases, the connections are more permanent in nature.
Some types of connections are established with the capability of self-rerouting if faults or other problems arise which by inference mean that the flow of data over the connection will be negatively affected (e.g. A physical link failure stops data flow on all connections on that link). One such type of connection is a soft permanent virtual connection (SPVC), which is a type of connection often employed in asynchronous transfer mode (ATM) networks. SPVCs provide an advantage in that the network manager does not have to interact with every switch along the path of the SPVC, but rather merely configures the endpoints and the network is able to select an appropriate path over which to map the SPVC. SPVCs provide an advantage in that they can quickly recover from faults that impede the flow of data.
In prior art systems, reroutes of SPVC connections are typically triggered upon detection of control plane faults (e.g. signaling link failure) or physical layer faults (e.g. physical link failure). Detection of such faults is used to infer a fault in the user plane of the SPVCs that are controlled by the signaling link or riding on the physical link. Similarly, the lack of such control plane faults and physical layer faults is used to infer the well-being of the user plane connections that they manage. However, the actual status of the user plane connection itself at the ATM layer, or at a similar layer in other protocol networks, is not used in such prior art systems as a potential trigger for rerouting an SPVC. This is undesirable, as the well being of the user plane connection itself is what subscribers, or users of the network, perceive. In some instances, the user plane may be experiencing problems that are not evidenced by faults detectable in the control plane or physical layer entities. As such, a user plane fault may not trigger a reroute while still causing problems.
Therefore, a need exits for a method and apparatus for rerouting connections that is capable of detecting user plane faults that may not be detectable using control plane or physical layer monitoring.